Unidirectional control mechanism for a sliding closure member



April 16, 1963 H. s. cARLsToN 3,085,300 UNIDIRECTIONAL CONTROL MECHANISM FOR A sLInING cLosuRE MEMBER Flled Jan 18. 1960 4 Sheets-Sheet l April 16 1963 H s. cARLsToN 3,085,300

UNIDIRECTINAL CONTROL MECHANISM FOR A SLIDING CLOSURE MEMBER Filed Jan. 18, 1960 4 Sheets-Sheet 5 /l45 e v HAM/L TON S. CA RLS TON INVENTOR HUEBNER 8 WO/PREL ATTORNEYS April 16, 1963 H. s. cARLsToN UNIDIRECTIO 3,085,300 NAL CONTROL MECHANISM FOR A ASLIDING CLOSURE MEMBER 4 Sheets-Sheet 4 Filed Jan. 18, 1960 United States Patent C) 3 085 300 UNIDIRECTINAL CNTRL MECHANISM FOR A SLIDING CLOSURE MEMBER Hamilton S. Carlston, 556 Tower Ave., Fresno, Calif. Filed Jan. 18, 1960, Ser. No. 2,379 2li Claims. (Cl. 2t) 52) The present invention relates to a unidirectional control mechanism for a sliding closure member and more particularly to such a mechanism selectively operable in an open position of such a member to limit further opening of the member until after movement thereof into closed position. r

The mechanism of the subject invention is especially adapted for sliding windows, doors, and like closures. For example, such a closure is typified by a rectangular, horizontally slidable window employing a metal sash. It is quite common to leave these, and other types of sliding windows, open at various times, to provide controlled extent of ventilation.

`While such conventional slide windows or doors can be locked in closed position, when they are slightly ajar, they can usually be opened yfarther by manipulation from the outside. Thus, they afford a convenient means of entrance into a building by intruders. The essence of the subject invention resides in the provision of a closure control mechanism which precludes or inhibits unauthorized opening of closures with which it is associated but facilitates authorized opening and closing operations.

Accordingly, it is an object of the present invention to provide a unidirectional control mechanism for sliding closures, and the like.

Another object is to provide a closure control mechanism which is selectively operable to open and to close closure members but which precludes opening such closure mem-bers by other means when partially opened unless rst moved to fully closed position.

Another object is to minimize the opportunities for unauthorized intrusion into buildings by external manipulation of closure members for the buildings.

Another object is to allow a sliding closure to be left partially open for ventilation purposes without fear that the `closure will be further opened -by an unauthorized intruder, such as a burglar, for gaining entrance to the building.

Another object is to provide a unidirectional control mechanism which is easily incorporated in conventional sliding closures of the type described.

Another object is to provide such a control mechanism which is adaptable for -use with a sliding closure member, including both doors and windows, and irrespective of the attitude or orientation of such a member.

Another object is to preclude removal of a sliding sash from a frame for the sash when the sash is in a closed or partly closed position.

Another object is to enable removal of a sliding sash from a frame therefor when the sash is in predetermined open position.

Another object is to provide a unidirectional control mechanism of the character described which is simple and economical to make and use, dependable in action, durable in construction, and highly effective for accomplishing its intended purposes.

These, together with other objects, will become more fully apparent upon reference to the following Adescription and accompanying drawings.

In the drawings:

FIG. 1 is a fragmentary side elevation of a Ibuilding wall in which is mounted a sliding window having inner and outer sashes and incorporating a control mechanism embodying the principles of the present invention.

ICC

FIG. 2 is a fragmentary, somewhat enlarged, vertical longitudinal section of the window of FIG. 1, showing in full lines a side elevation of the subject mechanism with the inner sash in fully closed position, and showing in dashed lines a side elevation of said mechanism with the inner sash partially open.

FIG. 3 is a fragmentary, somewhat enlarged, horizontal section taken on line 3 3 of FIG. 1.

FIG. 4 is a fragmentary, longitudinal, vertical section taken on line 4 4 in FIG. 3.

FIG. 5 is a fragmentary, transverse, vertical section taken on a plane at a position represented by line 5 5 in FIG. 4 showing a latching pi-n in unlatched position.

FIG. 6 is a fragmentary, transverse vertical section taken on line 6 6 of FIG. 2. but showing the latching pin in latching position.

FIG. 7 is a horizontal, fragmentary section of a sliding window incorporating a unidirectional control mechanism embodying a second `form of the present invention.

FIG. 8 is a transverse, fragmentary, vertical section taken on a plane at a position represented by line 8 8 in FIG. 7.

FIG. 9 is a fragmentary side elevation of a sliding window incorporating a um'directional control mechanism embodying a third `form of the present invention.

FIG. 10 is a fragmentary, horizontal section taken on line 10 10 in FIG. 9.

FIG. 11 is a somewhat enlarged, fragmentary, horizontal section taken on line 11 11 in FIG. 9.

FIG. 12 is a fragmentary, vertical longitudinal section of a window incorporating a fourth form of the subject invention.

FIG. 13 is a fragmentary side elevation of a portion of the structure illustrated in FIG. l2. and showing the sash of the window thereof in an open position.

FIG. 14 is a fragmentary, transverse section taken on line.14 14 in FIG. 13.

Referring more particularly to the drawings, a wall of a building is partially illustrated in FIG. 1 and is identiiied by the numeral 20. A sill 21 is connected to the wall and is outwardly extended therefrom into a room, not shown, of the building. The Wall provides a window opening in which a sliding window, generally indicated by the numeral 2.2, is mounted.

The window 2v2 includes a substantially rectangular frame 30 of channel-shaped cross-section. 'I'he frame provides a longitudinal upper frame portion 3.1, a front transverse or side frame portion 32, a bottom longitudinal frame portion 36, and a back transverse or side frame portion 34. As seen in FIGS. 2 and 3, the frame includes inside, intermediate, and outside flanges, 35, 36 and 37 defining circumferentially extended inside and outside grooves 39 and 40.

The window 22 also provides outer and inner, rectangular sashes 44 and 45 individually fitted in the outside and inside grooves 40 and 39, respectively, of the frame 3G. The inner sash provides spaced, parallel, upper and lower longitudinal sash portions 46 and 47 and spaced, parallel, vertical, front and back side or transverse sash portions 48 and 56 interconnecting the upper and lower sash portions. The inner sash is longitudinally slidable in the frame along a rectilinear path. A handle 52 is mounted on the inside flange 35 of the back sash portion for sliding the inner sash between a forward fully closed position with the front frame and sash portions in engagement, as viewed in FIG. 1, and a rear fully open position, not shown, but with the front sash portion 48 longitudinally spaced from the front frame portion 32 by a distance equal to the spacing between the back frame and sash portions I341 and 50 when the sash is in fully closed position, as is believed evident and well-known in sliding windows of this type.

The inner sash 45 has a transverse dimension measured between the upper and lower sash portions 46 and 47 which is less than the transverse distance between the upper and lower frame portions 31 and 33. Therefore, limited movement of the inner sash transversely of the path of movement thereof is permitted within the frame. An elongated retaining plate 55 is connected to the upper frame portion `31 within the inside groove 39 and is extended longitudinally ofthe path of movement of the inner sash. The retaining plate has a forward end 56 which is in rearwardly spaced relation to the front frame porion 32 and a rear end 57 in forwardly spaced relation to the back sash portion 50 even when the inner sash is in its fully closed position, as shown in FIG. l. -It is evident, therefore, that the rear end of the retaining plate is also in forwardly spaced relation to the front sash portion 48 when the inner sash is in its fully open position, as described above. When the inner sash is in fully open position, it is removed from the frame 30 by lifting it upwardly within the frame until the lower sash portion 47 is above the bottom frame portion 33. The lower sash portion is then moved transversely outwardly of the frame to incline the inner sash with respect to the outer sash 44. In this manner the inner sash can be readily removed fromV the frame. However, when any part of the inner sash is underneath the retaining plate 55, the inner sash cannot be moved upwardly within theframe a suilicient distance to bring the lower sash portion above the bottom frame portion. Thus, when the front sash portion moves forwardly underneath the rear edge 57 of the retaining plate, the inner sash cannot be lifted out of the frame. It is only when the inner sash is moved into fully open position that the inner sash can be removed as described.

An elongated ratchet plate 6i) is secured to the inside flange SS-of the bottom portion 313 of the window frame 30 and is extended outwardly therefrom in a substantially horizontal plane below the upper edge of the inside flange. The ratchet plate preferably extends the full length of the window and hasopposite end portions 61 and 62 respectively adjacent to the opposite side portions 32 of the frame. The ratchet platey provides a plurality of longitudinally spaced, longitudinally aligned, locking notches 64, 66, l68, 70 and 72 positioned in a row intermediate the opposite end portions of the plate. Each locking notch has a forward upwardly inclined slant edge or ramp 74 and a rear vertical edge 75. Further, the ratchet plate includes a plurality of detent apertures 77 also positioned in a row in olf-set relation to the row of locking notches. The detent apertures are in longitudinally spaced, aligned relation in their row. Further, the detent apertures are located in forwardly spaced relation to the forwardmost locking notch 64.

A generally rectangular housing 85 includes a top wall 86, and outer wall S7, and a pair of side walls 88 in spaced relation to each other and connected both to the top wall and to the outer wall. The housing is connected interiorly of the inner sash 45 at the intersection of the lower portion 47 and the back portion 50 at the lower-rear corner of the inner sash, as illustrated in FIGS. l, 2, and 3. Preferably, elongated screws 90 are extended through the outer wall and into the back land lower portions of the sash thereby releasably but dependably mounting the housing on the inner sash. The housing has a downwardly disposed opening, best seen in FIG. 4, but the outer and side walls of the housing are in closely adjacent, upwardly spaced relation to the ratchet plate 60.

With particular reference to FIG. 4, a pair of blocks 95 are connected to the outer wall 87 within the housing 85 by screws 86. These blocks are in longitudinally spaced relation to each other, with respect to the path of motion of the sash 45, and define a vertically disposed channel 97. A guide bolt 99 includes a shank 100 screwthreaded in the outer wall of the housing and extended into the housing below the blocks in vertical alignment with the channel and has a head 101 in spaced relation to the outer wall of the housing.

A locking pawl 105 includes aV pendent flange 106 having an elongated, longitudinally extended slot 157 therein longitudinally slidably `'fitted on the shank 100 of the guide bolt 99. The flange provides a locking tooth 168 downwardly extended therefrom. The locking pawl also has an upper shoulder 116. slidably iitted in the channel 97 and includes lower camming and latching surfaces 111 and I11.2. in elevationally offset relation to each other as well as being laterally outwardly extended from the flange 106. The camming and latching surfaces are also in upwardly spaced, substantially parallel relation to the ratchet plate 6i). It is also to be noted that the pendent flange 106 and therefore the locking tooth 108 are in a common vertical plane, disposed longitudinally of the plate 6ft, with the locking notches 64, 66, 68, 70, and 72. The locking pawl is thus mounted for vertical movement between a retracted position with the tooth disengaged from the ratchet plate 6l), as illustrated in FIGS. 2 and 6, and a locking position, as illustrated in FIGS. 4 and 5, with the locking tooth slidably engaging the plate and adapted to extend into the locking notches when the same are in individual Vertical alignment with the tooth. The locking pawl has an upwardly opening bore 115, and a pawl depressing, compression spring 116 is iitted in the bore and bears against the top wall 86 of the housing l85 for resiliently, yieldably urging the pawl into its locking position. When the locking tooth is not in alignment with any one of the locking notches, the spring thus urges the tooth against the ratchet plate and the tooth simply slides over the plate during movement of the sash 45 longitudinally in the groove 39.

It is to be observed in dashed line in FiG. 2, for example, that when the locking pawl 165 is in locking position, and when the tooth 108 is in alignment with one of the locking notches, as 64,the rear vertical edge of the tooth in abutting the rear vertical edge 75 of the notch precludes rearwardmovement of the sash 45 toward the next -adjacent notch 66. However, the locking tooth has a forward bevelled edge which slides over and upwardly along the forward slant edge 74 of each locking notch to permit movement of the sash toward closing position.

An elongated bushing sleeve 12d is connected in the outer wall `87 of the housing 85 in a vertical plane which intersects the latching surface 112 of the locking pawl 165 tr-ansversely of the grooves 39 and 4l). The sleeve is substantially the same distance from the ratchet plate 60 as said latching surface when the pawl is in fully retracted position. A latch pin 121 includes an elongated shank i122 longitudinally slidably fitted in the sleeve, an inner head 123 connected to the shank `and located within the housing, an intermediate disk 12S `also connected to the shankbut located outside of the housing, and an outer manipulating knob 126 connected to the shank in longitudinally endwardly spaced relation to the intermediate disk. The latch pin is slidable inwardly into an inner latched position when the pawl 105 is in 'fully retracted position to `allow the inner head of the pin to extend underneath the latching surface 112. Thus, the latch pin holds the pawl in retracted position against the depressing urgency of the spring 116. The latch pin is also slidable outwardly into an unlatched position, as illustrated in FIG. 5, with the inner head against the sleeve and out from under the latching isurface to permit the spring 116 to depress the pawl.

A camming wheel 130 is rotatably mounted on the shank 10i) of the guide bolt 99 between the pawl 105 and the outer wall 87 of the housing S5, `as best illustrated in FIGS. 4, 5, and 6. This wheel is located in a vertical plane disposed longitudinally of the plate `60 and passing through the detent apertures 77 in the ratchet plate. The camming wheel includes a plurality of circumferentially spaced, substantially radially extended detents `131 individually adapted to lit into the detent apertures upon movement of the sash 45 into a position with the housing 85 over the detent apertures, in a manner to be explained. The wheel also has a camming edge 133 extended circumferentailly of the wheel, eccentrically of the shank 100, and between the outermost detents 131. This camming edge slidably engages the camming surface 111 of the upper shoulder 110 of the locking pawl 105 when the locking pawl is urged into its locking position by means of the spring 116. The wheel is rotatable in opposite directions ybetween angularly related releasing and retracting positions with the detents extended `generally forwardly and rearwardly, respectively, as illustrated in FIG. 2. 1n the retracting position of the wheel, the camming edge -holds the pawl upwardly in its fully retracted position while in the releasing position, the camming edge allows the spring to urge `the pawl into its locking position. When the inner sash is in fully closed position, as viewed in FIG. 2, an endmost detent is extended into the forwardmost detent aperture 7-7. The spacing between adjacent detents is related to the spacing between the detent apertures so that as said sash is opened, the intermediate detent lits into the intermediate detent aperture, and so on, so as to rotate the camming Wheel in response to sliding movement of the sash. As the sash moves toward open position, therefore, the camming wheel lgradually lowers the paw1 1tl5 into its locking position. The detent last to fit into and emerge from the rearwardmost aperture slides along the ratchet plate 60 land is urged thereagainst by a cam depressing leaf spring 135 connected to the forward block 95 within the housing 85 and bearing against the uppermost detent in the releasing position of the Wheel, as viewed in FIG. 4. The number and spacing of the apertures and detents can be varied, if desired, as long as there is a corresponding relation therebetween.

Operation The operation of the described embodiment of the subject invention is believed to be readily apparent and is brielly summarized at this point.

Assuming that ventilation is desired through the window opening in the Wall 20, Without the intrusion of unauthorized persons, the inner sash 45 is slid a slight disstance to the right, as viewed in FIG. 1, so as to provide a space between the front sash portion 48 and the front frame portion 32. The rear sash portion '58 might then be in a position such as is illustrated in dashed lines in FIG. 2. The opening provided is too small to permit an intruder to enter but is suliicient to provide ventilation. With the Window in partially open position, as described, the latch pin 1211 is pulled outwardly into unlatched position, as viewed in FIG. 5. This allows the spring 116 to urge the locking pawl 105 downwardly against the ratchet plate 611 into its locking position'.

Continuing the assumption that the inner sash 45 is opened to the positon illustrated in dashed lines in FIG. 2., the spring 116 urges the locking tooth 188 into the locking notch 70. Thereafter, further opening of said sash is precluded because of the engagement of the rear edge of the locking tooth with the rear vertical edge 75 of said locking notch. Since the space provided between the front sash portion It8 and the front frame portion 32, even when the locking tooth is extended into the rearwardmost locking notch 72, is inadequate to allow an intruder to pass therethrough, it is evident that the subject mechanism precludes unauthorized entry.

However, the sash 45 may be moved from the dashed line position of FIG. 2 toward fully closed position inasmuch as the forward edge of the locking tooth 108 can slide upwardly out of each locking notch 64, 66, 68 and 7 0 along the forward slant edge 74 of each notch. When the sash has been closed suiciently to bring the downwardmost `detent 131, in the releasing position of the cam Wheel 130, into alignment with the rear detent aperture 77, the cam Wheel is turned in a counterclockwise direction, as viewed in FIG. 2. Subsequent fitting of the other detents into the -successive apertures completes the movement of the camming wheel into pawl retracting position wherein the camming edge 133 raises the pawl out of engagement from the ratchet pl-ate 60 and moves the latching surface 112 above lthe inner head 123 on the latch pin 121. However, this does not occur until the sash is completely c-losed. Thereafter, the latch pin 121 can be moved inwardly into latched position with the inner head under fthe latching surface 112 to hold the locking pawl in its retracted position and to allow lthe sash to be freely moved into any open position desired. While any one attempting entry through the partially open sash t5 could close Ithe inner sash, such person could not thereafter move the latch pin i-nto latched position because the pin is on the inside Iof the window. Therefore, mere closing of -said sash is insuiiicient to release the looking mechanism. Unless the latch pin is thrust inwardly when the sash is fully closed, the lock-ing -tooth is still urged into the forwardmost notch upon opening of the sash.

Second F orm The second form of the subject invention is illustrated in FIGS. 7 and 8 and is embodied in a par-tially illustrated window frame 1'50 including a horizontal bottom por-tion '151 providing inside, intermediate, and outside flanges 152, 153, and 154, which flanges provide elongated, longitudinally extended, inside and outside grooves 156. An upstanding front transverse or side portion 158 of the frame is also illustrated.

An elongated ratchet plate is mounted longitudinally on the inside flange 152 -by means of screws 166 in transversely vertical position. As with Athe irst form of the subject invention, this ratchet plate has a plurality of longitudinally spaced, longitudinally aligned locking notches 167 each of which has a rear edge 168 perpendicular to the inside flange and a forwardly outwardly extended slant edge 169 obliquely related to said inside flange.

The inside llange 152 of the frame 150 and the ratchet plate 165 adjacent to the front frame portion 158 respectively provide an opening Iand a socket 176 in alignment with each other. A camming stud 178 is fitted in the opening and the socket `for axial sliding movement transversely of the ratchet plate and inside flange between a retracted position extended into `the inside groove and iiush with the ratchet plate, as viewed in FIG. 7, and a camming position extended outwardly from the ratchet plate 165 and internally flush with the flange 152, not shown but believed evident by reference to FIG. 7. A disk 179 is connected to the stud and engages the inside flange of the lframe in the retracted position of the stud. A coiled compression spring 130 -circnmscribes the stud and lbears against the disk and the ratchet plate for yieldably, resiliently urging the stud into said retracted position.

A window sash is partially shown in FIGS. 7 and 8 and includes a lower portion 186, and a front side or transverse portion 187. The sash is slidable in the inside groove 156 of the frame 150 between a completely closed position with said front sash portion engaging the front frame portion 158 of the frame and a plurality of open positions wherein said side portions are spaced from each other, as illustrated in FIG. 7. The sash, of course, mounts a window pane 189. It will -be evident that when the camming stud 178 is extended into the inside Igroove 156 in retracted position, it is in the path of travel of the front side portion of the sash as it moves towards closed position.

A cylindrical housing is rigidly mounted on the lower portion 186 of the sash 185 adjacent to the front portion 187 by means of a bracket 196. r[he housing is supported in outwardly closely spaced relation to the ratchet plate 165 and has an elongated substantially concentric bore 197 substantially normal to 4the plate. The

able with the notches 167 upon longitudinal movement of' the sash in the inside groove 156.

An elongated cylindrical locking pawl 2% -is longitudinally slidably iitted in the bore 197 and has an inner forward, bevelled edge 201 obliquely related to the plate and adapted to extend individually -into the notches l167 of the ratchet plate 165 when the bore is in alignment with such notches. The pawl also has a rea-r edge normal to the plate. Also, it is to he observed that the pawl and the stud 17S are in a substantially common horizontal plane. A plug 202 is .screw-threaded in the outer end of the bore, and a coiled compression spring 203 isY interposed the plug and the pawl for yieldably resiliently urging the pawl into a 'locking position in engagement with the ratchet plate when the pawl is not in alignment with one of the notches, or into such notches when such alignment exists. The pawl has an annular latching recess 205 intermediate its opposite ends, for a purpose to be described. Also, the housing 1915 has a ilange 206 extended under the ratchet plate to limit elevational adjust- -men-t of the sash 185 and to preclude its removal from the frame 151, in the manner described in connection with the inner sash `45, except by removing the screws '166.

An elongated bushing sleeve 21@ is connected in the housing 195 and extends diamet-rcally outwardly therefrom. A latch pin 211 is slida'bly mounted in the sleeve and includes a shank 212 adapted for extension transversely into the bore 197 of the housing. A disk 213 is connected to the shank for l-imiting outward movement of the pin by engagement with the sleeve, as illustrated in FIG. 7. The pin also has an outer knob 215 IJfor convenience -in adjustment of the pin. When the pawl 20u is in fully retracted position within the housing, the recess 205 is in alignment with the shank of the pin so that if the pin is moved inwardly of the sleeve, the shank fits into the recess and holds the pawl in a retracted position.

In the operation of the second form of the subject invention, the control mechanism may be actuated by pulling the latch pin 211 outwardly into an unlatched position thereby allowing the spring 2113 to urge the pawl 2%' into locking position in engagement with the ratchet plate 165. It will be evident that opening movement of the sash 18S-is limited since upon alignment of the bore 197 `and any one of the notches y167, the pawl 201i is urged into the notch whereby the rear edge. of the pawl engages the rearedge 16S of the notch to preclude further openingl movement of the sash. However, -as before, closing movement of the sash is allowed because the bevelled edge 201v of the pawl slides over the slant edges `169 of the locking notches.

in order to release the pawl 2%, it is necessary to move the sash 185 into completely closed position. When the sash is so moved, the front sash portion 137 engages the inwardly extending camming stud 175 and urges the same into its camming position. Simultaneously, the bore 197 is aligned with the stud so that the sash urges the stud into engagement with the pawl 2d@ and forces the pawl into retracted position into the housing 195. With the pawl in fully retracted position, the recess 205 is in alignment with the latch pin 211. By moving theV latch pin into latched position, the pawl is held in retracted position, `and the sash may be freely moved into any open position desired.

T hiral Form The third form of the subject invention is'illustrated in FiGS. 9, 10, and ll. A window frame is partially illustrated in FGS. 9 `and l0 and is identiied generally by the number 22d. This frame, as best illustrated in FIG. l0, includes transversely spaced inner, outer, and intermediate flanges 221, 222, and 223. As before, these flanges provide inner and outer grooves 225 and inner and outer sashes 23u and 231, each havingwindow panes 232', are' individually'slidably mounted in the inner and outer grooves 225 and 226, respectively. Each 7 have opposed L-shaped flanges '236 in interitted engagement, as illustrated in FlG. l0, lwhen both sashes are in fully closed positions in the window opening.

An elongated ratchet plate 24a@ is connected by means of screws 2&1 to the lower portion 233 of the outer sash 231 in a vertical position. The ratchet plate is, of course, on the inside of the sash and is extended longitudinally of the lower portion slightly above the upper edge of the ianges 221 and 223. This plate has a plurality of longitudinally spaced, longitudinally aligned, generally sawtoothed, locking notches 242 each of which has a rear slant edge 24A and a forward normal edge 245. Also, as best seen in FlGS. 10 and '11, the ratchet plate has a camlning tongue 247 extended outwardly therefrom toward the inner sash 230'- and adjacent to the L-shaped flange 236 onv the side portion 23d-of the outer sash. Otherwise stated, this tongue is in alignment with the notchesV in rearwardly spaced relation to the rearwardmost notch.

A housing `255 is secured tothe rear portion 234 of the inner sash 23d and is slidably movable in the inner groove 225 alongwith the inner sash. The housing has a longitudinally extended inner wall 256,' an outer wall 257, and a rear transversev wall 255 connecting the longitudinal walls.

The housing 255 provides a cavity 260 partially deiined by the rear side portion 234 of the inner sash 23d and opening outwardly of the housing tolward the ratchet plate 24?. A generally cylindrical pawl 261 is slidably fitted in the cavity for movement transversely of the path of travel of the sash betweenV a fully retracted position within the housing and a locking position extended outwardly of the housing into engagement with the ratchet plate or extension into the locking notches 242 depending on whether the p'awl'is in alignment with the notches or not, as is believed understood'. The pawl has a endward bore 262, and `a pawl depressing spring'263 bears against the outer wall 257 of `the housing and extends into the bore yieldably, resiliently urging the pawl into locking position. The pawl also has a forward bevelled edge 264, a rear normal edge, an annular shoulder 265 adapted for engagement with the outer wall 257 of the housing toV limit outward movement of thepawl in locking position, and a lug 267.

An elongated latching pin 275 includes a shank 276 slidably extended through the transverse Iwall 25S of the housing 255 and movable into the cavity 26d. The pin also vincludes a head 277 connected to the shank, an outer manipulating knob 278, and a pair of axially spaced, annular recesses 279. A' spring pressed detent 281 is provided in the housing for individual releasable reception in the recesses in the shank for holding the latch pin in either a fully unlatched position, as illustrated in FIG. 1l, or a latched position, not shown, but described below.

In the operati-on of the third form of the subject invention, it is iirst assumed that the L-shaped flanges 236 are separated so that the inner and outer sashes 236) and 231 are respectively moved toward the left and right in FIG. 10. Thus, the sashes would both be in a partially open position. In order to actuate the locking mechanism of the third form of the invention, the latch pin 275 is pulled outwardly until the detent 281V engages the innermost recess 279. This frees the pawl 261l for movement intoengagement with the ratchet plate 240x When, for example, the sash 2311 is moved to provide a wider opening at its respective side of the window, the pawl eventually aligns with one of the notches 242. Thereupon, the springs 263 press the pawl into the notch. Further opening movement of said sash 250 is 9 precluded because of abutment of the rear edge of the pawl with the forward edge 245 of the notch, as illustrated in FIG. 11. The other sash 231 could be opened a similar amount by completely closing the sash 230 but .this would be of no aid to an intruder.

In order to release the pawl 261, it is necessary to close both the sashes 230 and 231 so that their L-shaped flanges 236 are once again interlocked, as illustrated in FIG. 10. Upon closing the sashes, the bevelled edge 264 of the pawl slides over the slant edges 244 of the notches 242. When the pawl engages the tongue 247 on the ratchet plate 240, the pawl is urged into retracted position in the housing 255. With the tongue still engaging the pawl, the latching pin 275 is moved into its latched position with the head 277 inwardly of the lug 267, toward the ratchet plate, so that the pawl is held in retracted position against the urgence of the spring 263. Thereafter, the sashes 230 and 2311 may be opened or closed individually, as desired.

Fourth Form With particular reference to FIGS. 12, 13, and 14, a window frame is illustrated and generally indicated by the numeral 300. Although only part of the frame is shown, it is to be understood that it is substantially rectangular like the frame 30 in the first form of the subject invention. Insofar as the fourth form is concerned, however, the frame therefor has a lower elongated, longitudinal frame portion 301 including inside, intermediate, and outside flanges 303, 304, and 305, with said flanges providing inside and outside grooves 307, as before. For purposes of reference, the lower portion of the frame has a front end portion 309 and a rear end portion 310.

A substantially rectangular sash 315 is tted in the inside groove 307 of the frame 300 for longitudinal slidable movement therein and includes a back, upright transverse portion 317 and a bottom longitudinal portion 318. Once again, it is to be understood that the sash '315 is constructed like the sash 45 of the iirst form of the present invention. The sash is movable longitudinally of the frame between a fully closed position in the opening provided by the frame, as illustrated in FIG. 12, and a fully open position, not shown, but with the back sash portion rearwardly spaced from its position in FIG. 12.

An elongated ratchet plate 320 includes a vertical mounting flange 321 tted against the inside flange 303 of the frame 300 and providing vertically extended, elliptical openings 322. Screws 323 are individually extended through the openings and into the frame for securing the ratchet plate to the frame. The plate also has a horizontal elongated flange 325 extended substantially perpendicularly outwardly from the inside ange of the frame and providing a forward end 326 and a rear end 327 respectively relatively adjacent to the front and rear ends 309 and 310 of the lower longitudinal portion 301 of the frame. It is also to be noted that the horizontal flange provides an upper surface which is smoothly, arcuately, downwardly curved at the rear end thereof.

The horizontal flange 325 is provided with a row of longitudinally spaced, saw-tooth, locking notches 330 in its upper surface, each notch having a -rear upright edge 331 substantially normal to the upper surface of the horizontal flange and a forward slant edge 332 forwardly upwardly inclined from its respective upright edge. The horizontal flange also includes a forward elongated slot 334 longitudinally extended in the horizontal flange and having a rear edge 335 and a front edge 336. A camming arm 338 is pivotally mounted on the mounting iiange 321 by means of a horizontal pivot member 340 for pivotal movement of the arm in a vertical plane. The arm is upwardly extended within the slot and is movable between a retracted position against the rear edge of the slot and a camming position toward the front edge of the slot. Although the arm is gravitationally urged into retracted position in the illustrated embodiment in FIG.

l2, a coiled spring 342 can beprovided on the pivot member in engagement with the arm for yieldably urging the arm into retracted position. For example, the coiled spring would be required if the sash 315 and thus the ratchet plate 320 were mounted in an upright position.

A housing 350 is secured to the back portion 317 of the sash 315 by means of bolts 351. The housing has a lower surface `353 in closely adjacent, opposed relation to the upper surface of the horizontal flange 325, front and rear vertical surfaces 354 and 355, and a top surface 357.

An L-shaped flange 360 is extended downwardly from the lower surface 353 of the housing 350 and thence horizontally inwardly toward the mounting flange 821 and under the horizontal flange 325 of the ratchet plate 320, as best illustrated in FIG. 14. While the lower surface of the housing and the L-shaped flange slidably receive the mounting flange therebetween, the L-shaped flange limits elevational or transverse movement of the sash 315 with respect to the frame 300, as will be understood more fully hereinafter. Further, a finger 362 is rigidly inwardly extended from the L-shaped flange toward the mounting flange and thus underneath the horizontal flange of the ratchet plate. The finger is movable with the sash in a longitudinal path which intersects the camming arm 338 so that when the sash is substantially in fully closed position, the nger engages the arm and urges the same in a clockwise direction from its retracted position into its camming position.

The housing 350 has a vertical bore 370 therein opening through the lower surface 353, in substantial alignrnent with the linger 362, Vand registrable with the slot G34 in the substantially fully closed position of the sash 315. The housing has an internal annular shoulder 37-1 circumsciibing the vertical bore. The housing also provides a substantially horizontal bore 373 opening into the vertical bore and outwardly of the housing through the front surface 354. Furthermore, the housing provides an upright socket 375 offset from the vertical bore and opening into the horizontal bore.

A ratchet pawl 380 is longitudinally slidably fitted in the vertical bore 370 foimovement between a locking position extended outwardly below the lower surface 353 of the housing 350 in engagement with the horizontal ilange 325 of the ratchet plate 320, and a retracted position inwardly spaced in the bore from the lower surface of the housing. llt is to be noted that the pawl has a collar 38-1 engaging the shoulder 371 in said locking position for limiting outward movement .of the pawl relative to the housing. The pawl also has an inner, inwardly tapered, clonical head 383 with the base of the head in longitudinally `spaced relation to the collar Iand defining an annular recess 384 therebetween. A plug 358 is screw-threaded in the bore from the top surface 357, and a coiled compreslsi-on spring 386 is interposed the plug and the head for yieldably urging the pawl into locking position. It is to be noted, however that the maximum diameter of the spring is substantially equal to the minimum diameter of the head yso that the spring engages the head adjacent to its apex. A spring guiding stud 337 is endwardly concentrically extended from the apex of the head 383 and is positioned within the spring.

An elongated latch pin 390 has a major Ishank 391 axially slidably fitted in the horizontal bore 373, a minor shank 392 axially extended from the major shank in concentric, ci-rcumferentially spaced relation within the bore 373, an inner disk 393 connected to the minor shank in axially spaced relation to and of the same diameter as the major shank, and a camming peg 394 inwardly axially extended from the disk.

A screw 395 is threaded into the socket 375 from the l'ower ysurface 353 of the housing 350. A block 396 is 4also tted in the socket ifor axial movement therein. A coiled compression spring 397 is interposed the blook and the screw for yieldably urging the block into the horizontal bore between the major shank 391 and the disk land into engagement with-the-minor shank 392 of the latch pin 390-.V When the pawl 38h? is in ful-ly retracted position, so that the recess 384 is in alignment with the horizontal bore 373, the latch pin is movable between a latching position, with the peg 394extended into the recess between tne head 333 and the collar 381, as viewed in FIG. 12, and a-retracted position with the peg laterally outwardly spaced from the base of the head, as viewed in FIG. 13. In the latching position, the peg is engageable with the base of the head and precludes movement of the pawl into locking position. Engagement of the disk with the block precludes removal of the pin from the horizontal bore in the retracted position of the pin.

In order to actuate the latching mechanism, 4the latch pin 390 is pulled outwardly into its retracted position, illustrated in FIG. 13. This allows the spring 336` yieldably to urge the pawl 380 downwardly into engagement with the flange 325. In this intermediate position of the pawl, referred to hereinafter, the peg 394 is opposite to the head 383 between its apex and base sand also between said base `and the spring. Therefore, if the sash 315 is moved rearwardly into lopen position, and the pawl is aligned with one of the locking notches 334i, as illustrated in FG. 13, the pawl is extended downwardly into the notch and into engagement with the rear upright edge 331. This precludes further opening of the sash, in the same manner as described in connection with the other forms of the present invention. However, as before, the sash can be moved toward closed position since the pawl simply rides upwardly along the inclined edge or edges 332 onto the upper surface of the mounting flange, If the peg happens to be in engagement with `the iside of the head, it does not resist movement of the pawl into locloing position and, in fact, pressure applied axially inwardly on the pin tends to urge the pawl into locking position because of camming engagement of the peg with the head.

As the sash 315 approaches fully closed position, the iinger 362 engages the iarm 338 and pivots the same up'- wardly into camming position. Simultaneously therewith, the vertical bore 376I is brought into registration with the slot 334 so that the farm is extended upwardly into engagement with the pawl to force the same into retracted position. It is to -be understood that the .arm extends upwardly into the vertical bore, as illustrated in FIG. 12, to press the pawl inwardly of the lower surface 353 of the housin-g 35o and to bring the recess 384 into alignment with the horizontal bore 373. Of course, to retain the pawl in retracted position, the latch pin 390 is then pressed inwardly into its latching position, as illustrated in FIG. 12. Thereafter, the sash can be moved into [any open position desired.

While it is described above that the latch pin 390 is moved into retracted position in the fully closed position of the sash 315, it is evident that said latch pin can be retracted in @any open position of the sash. If the latch pin is retracted when the vertical bore 37 t is rearwardly spaced from the rear end 327 of the ratchet plate 32o, the pawl 380 is, of course, moved downwardly into its locking position. Upon subsequent movement of the sash toward closed position, the pawl rides upwardly over the rear rounded off edge 327 of the horizontal ilange 325i and onto the upper surface thereof. As soon las the pawl aligns with the rearwardmost locking notch 330, it is urged downwardly thereinto for locking the 'sash against movement rearwardly of such position.

The advantage of the fourth form o-f the subject invention is that it prevents picking of the latching mechanism by insertion of a thin blade, or other member, not shown, between the lower surface 353 of the housing 350 and the mounting flange 321 thereby to press the pawl 330 upwardly into the housing in an effont to bring the recess 384 into alignment with the horizontal bore 373. That is, even if such a thin member were so inserted, it would be ineffective to push the pawl inwardly of the lower surface of the housing. It is of cour-se understood that such inward movement of the pawlfis necessary to. bring the recess into alignment with the'v `bore and thereby to allow latching insertion lof the latch. pin 390. Also, assuming the pawl is in said inter-mediate position spring-urged into engagement with the flange 325 and is between a pair of adjacent notches 330, and thus the window is open, an intruder cannot hold the pawl in said intermediate position by reaching through the opening and pressing in on the pin. Such pressing would tend to cam the pawl into locking position, as explained above, so that it would be forced into a notch upon alignment therewith.

The fourth form of the present invention also incorporates means for controlling removal of the sash 315 from the frame 300. Thus, as long as the L-shaped ange 366i is extended underneath the horizontal iiange 325, the sash cannot be lifted upwardly in the frame for removal thereof, as, described in connection with the first form of the present invention. However, when the L-shaped flange is offset in rearwardly spaced relation from the horizontal flange of the ratchet plate, the sash may be lifted with respect to the frame and removed therefrom in a manner believed evident. As with the first form of the invention, the interengaging flanges 360 and 325 insure locking engagement of the pawl 380 with the ratchet plate 320. After the pawl has moved rearwardly of the rearwardmost locking notch 330, there is no necessity of precluding removal of the sash from the frame by manipulation from within. yIn fact, when the sash is in such position, it is desirable to be able to remove the sash from the frame for repair, re-glazing and the like.

The first, second, and fourth forms of the invention are best suited for use with either a single sliding window sash or with a window within which there is a stationary sash and a sliding sash. As is believed evident, the third form of the invention is especially adapted for use with a sliding window having a pair of movable sashes. The third form of the invention has the advantage of preventing anattempted intrusion through the window by insertion of a long tool, not shown, through a small opening at one end of the window, which tool could have means for grasping the latching pin 275 and sliding it into latching position. Since it is necessary for both sashes to be closed before the pin 275 can be moved into latching position, a tool of the described type could not be employed. If the type of mechanism disclosed in the second form of the present invention were employed on each of two movable sashes in a common frame, as illustrated in FIG. 10, so that each mechanism and sash operated independently of the other, it would be possible for an intruder to extend such a tool through a small opening providedby one of the sashes, to grasp the latching pin 211 associated with the other closed sash with such a tool, and to move the pin into latched position. Thereafter, said other sash could be opened without restriction.

From the foregoing, it will be evident that a unidirectional control mechanism for sliding closures has been provided. While several forms of the mechanism have been dis-closed, it isL evident that a common principle governs operation of all of the mechanisms. Essentially, each mechanism is selectively operable in an open position of the closure thereby to limit further opening of the closure until after the closure has first been moved to fully closed position. The mechanisms are easily attached to conventional structures, are easy to operate, and are dependable in action.

Although the invention has been herein shown and describedinwhatis conceived to be the most practical and preferred embodiments, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and apparatus.

Having described my invention, what I claim as new and desire'to secure by Letters Patent is:

1. In a sliding closure including a support providing an opening and a sash slidably tted in the support for movement in opposite directions along a predetermined path between open and closed positions in the opening, a mechanism for limiting opening of the sash comprising a rst ratchet member borne by the support; a second ratchet member mounted on the sash and movable between a locking position engaging the rst ratchet member to preclude opening of the sash beyond a predetermined open position, and a position retracted therefrom permitting unrestricted sliding of the sash into fully open position, said second ratchet member being yieldably urged into locking position; control means engageable with said second ratchet member and operably associated with the iirst ratchet member to move the second ratchet member into retracted position only when the sash is in fully closed position; and a latch releasably engageable with the second ratchet member to hold it in retracted position.

2. In a support member, a controlled member mounted on the support member for reciprocal movement in opposite directions along a predetermined path, a unidirectional control mechanism for limiting movement of the controlled member in one direction until the controlled member is moved a predetermined distance in the opposite direction comprising a ratchet including an elongated ratchet plate having a notch therein, a housing, and a pawl mounted in the housing; means connecting the ratchet plate to one of the members; means connecting the housing to the other of the members, the pawl being movable in the housing transversely of said path between a locking position slidably engaging the plate and adapted for extension into the notch upon registration therewith, and a position retracted therefrom; resilient means in the housing yieldably urging the pawl into said locking position; latch means mounted in the housing for movement between a locking position engaging the pawl and holding it in its retracted position and an unlatched position permitting the resilient means to urge the pawl into the locking position; and camming means operably associated with the ratchet plate and engageable with the pawl upon movement of the controlled member a predetermined distance in said opposite direction to move the pawl into retracted position if the pawl is in locking position.

3. In a support, a member mounted on the support `for reciprocal movement in opposite directions along a predetermined path, a unidirectional control mechanism for limiting movement of the member in one direction until the member is moved a predetermined distance in the opposite direction comprising an elongated ratchet plate; means Imounting the ratchet plate on the support in ylongitudinally extended, adjacent relation to the path of movement of the member, the plate having a row of notches longitudinally -spaced and aligned along the plate; a housing supported on the member for movement therewith; a pawl slidably mounted in the housing in a plane coincident with said notches for movement transversely of said path between a locking Iposition slidably engaging the plate and adapted for extension into one of the notches upon registration therewith, and a retracted position disengaged from the plate; resilient means in the housing yieldably urging lthe pawl into said locking position; a latching pin mounted in the housing for movement between a latched position engaging the pawl and holding it in its retracted position yand an unlatched position disengaged from -the pawl and permitting the resilient means to urge it into locking position; and camming means operably `associated with the ratchet plate and engageable with the pawlupon movement of the member -a predetermined distance in said opposite direction to move the pawl into retracted position.

4. In a support, a substantially rectangular frame circumscribing an opening and a sash mounted in the frame for slidable movement in opposite `directions along a predetermined path -between 4open positions and a closed position in said opening; a mechanism optionally operable in an lopen position of the sash for limiting opening movement thereof yuntil the sash is first moved into closed position comprising 'an elongated ratchet plate; means mounting the ratchet plate on Athe trame in'longi-tudinally extended, adjacent relation to the path of movement of the sash, the plate having a row of notches therein facing the sash and longitudinally spaced and aligned along the plate; a housing supported on the sash for movement therewith; a pawl slidably mounted in the housing in a plane coincident with said notches for movement transversely of -said path between a locking lposition slidably engaging the plate and adapted for extension into one of the notches upon registration therewith, and a retracted position `disengaged from the plate; resilient means in the housing yieldably urging th-e pawl into said locking position; a latching pin mounted in the housing `for movement between a latched position engaging the pawl and holding it in its retracted position and an unlatched position disengaged from the pawl and permitting the resilient means to urge it into locking position; and camming means operably lassociated with ratchet plate and engageable with the pawl adjacent .to the closed position of the sash to move lthe pawl into retracted position if the pawl is in lock-ing position.

5. The mechanism of claim 3 wherein the pawl has an elongated flange mov-able longitudinally thereof between said locking and retracted positions and a camming shoulder transversely extended from the flange in laterally spacedI relation to the plate; wherein ythe ratchet plate has opposite end portions; wherein the camming means includes a `detent aperture in the ratchet plate offset from the row Iof notches and located in the end portion of the plate toward which the sash moves in closing, a camming wheel lrotatably mounted in .the housing in a plane substantially coincident with the aperture, the wheel being rotatable about an axis disposed transversely of s-aid path lin spaced relation 'to the plate .and having a camming edge eccentric to said axis yand in engagement with said camming shoulder, the wheel being rotatable in opposite directions between angularly spaced, pawl retracting and releasing positions, said camming edge sliding against said shoulder during rotation to eiTeot movement of said camming shoulder bet-Ween' a position closer to said axis in said releasing position than in said ret-racting position thereby to move the flange between locking land retracted positions, respectively, the wheel also including a radially extended detent engageable with the plate and in substantial alignment with the aperture; and resilient means engageable with the wheel in its releasing position and yieldably urging the detent against the plate so that when the sash is moved toward closed position, the detent is urged into the aperture thereby to rotate the wheel from releasing position to locked position and to allow the pawl to move into ratchet plate engagement.

6. 'Ilhe mechanism of claim 3 wherein the ratchet plate has lopposite end portions; Iand wherein said camming means includes an elongated stud mounted in the ratchet plate 'at the end portion thereof toward which the sash moves in closing for alternate and opposite movement into the path of the sash Iand into'the path of the pawl when fthe latter is in locking position, and means engaging the stud yieldably urging the stud into the path of the sash, `the sash being en-gageable with the stud in the closed position thereof to move the stud into the path of: the pawl, said pawl being'alignable with the stud in the closed position of the -sash whereby the pawl is urged into retracted position by the stud.

7. The mechanism of claim 1 wherein 'the rst ratchet member is an elongated plate extended longitudinally of the path of the sash and providing a plurality of longitudinally spaced locking notches; wherein the second ratchet member is a pawl mounted on the sash for movement transversely of said path between said locking position engaging .the plate and said retracted position, the pawl being in longitudinal alignment with the notches in said locking position ttor registration therewith incident to movement of the sash' along said path; and resilient means borne by the' `sash engaging the pawl and yieldably. urging it into locking position and into said notches upon registration of the pawl therewith.

8. The mechanism of claim 7 wherein said pawl includes a camming surface in spaced substantially parallel relation to the plate, wherein said control means includes a cam rotatably mounted on the sash -for rotatable, slidable, wedgable engagement between the ratchet plate and the camming sur-face lof the pawl as the sash moves into its closed position to move the pawl into retracted position when the sash is in its completely closed position.

9. The mechanism of claim 8 wherein the ratchet plate has longitudinally spaced, rst and second end portions, wherein the pawl and cam are adjacent to the iirst end portion in the fully closed position of the sash and adjacent to the second end portion in the fully open position of the sash, wherein the notches are located between said end portions, wherein said control means includes a plurality of detent apertures in the ratchet plate in longitudinally spaced relation to each other with respect to the plate, the apertures being offset from the notches transversely of the plate and being located between the iirst end portion of the plate and the notches, said cam being a wheel rotatably mounted on the sash for rotation about an axis disposed transversely of said path of movement and including an eccentric camming edge engaging the camming surface of the pawl and a plurality of circumferentially spaced detents extended substantially radially outwardly -from the axis on the opposite side thereof from said edge, the wheel being in a plane extended longit-udinally of the ratchet plate and coincident with the apertures, said eccentric edge having circumferentially spaced maximum and minimum radii, the wheel having a releasing position when the sash is open wherein the detents are directed toward the iirst end portion of the plate and wherein theminimum radial portion of the edge is in engagement with the camming surface, the Wheel also having a retracting position when the sash is completely closed wherein the maximum radial portion of the edge is in engagement with said camming surface, and the detents individually successively fitting into the apertures as the sash moves toward closed position and rotating the wheel to move said maximum radial portion into engagement with the camming surface.

l0. The mechanism of claim l wherein said second ratchet member is movable with the sash along said path between iirst and second positions spaced longitudinally of the path, said second ratchet member being in said first position when the sash is in closed position, and wherein said control means is a stud slidably mounted in the support adjacent to the first position of the second ratchet member for slidable movement transversely of the path of the -sash between a retracted position in the path of the sash and a camming position in the path of the second ratchetY member, resilient means borne by the support engaging the stud and urging the same into retracted position, wherein the second ratchet member is in alignment with the stud in said first position, and wherein the sash engages the stud in said closed position and moves the stud into its camming position in engagement with the second ratchet member to retract the same.

11. The mechanism of claim 1 wherein said second ratchet member is movable with the sash along said path between iirst and second positions spaced longitudinally of the path, said second ratchet member being in said iirst position when the sash is in closed position, `and wherein said control means is a tongue extended outwardly from the ylirst ratchet member adjacent to said irst position of the second ratchet member and in the path of travel thereof for engagement with the second ratchet member to move the same into its retracted position.

12. The mechanism of claim 3 wherein said camming means is a tongue rigidly projected outwardly from the I6 plate on the same side thereof as the housing and in the path of travel of the pawl for engaging the pawl and `forcing it into retracted position.

13. In a rectangular frame having opposite longitudinally spaced side portions; iirst and second sashes having inner side portions and extended portions, the sashes being mounted in the frame in spaced parallel planes for movement .along individual paths between closed positions with their inner side portions in adjacent relation to each other, and open positions with said inner portions spaced apart; an elongated ratchet plate mounted on the rst sash and extended longitudinally of the path of movement of said sash, the plate providing a plurality of longitudinally `spaced locking notches directed toward the second sash; a pawl mounted on the second sash for .movement transversely of the path of the second sash between a locking position engaging the ratchet plate and in alignment with the notches, and a retr-acted position disengaged from the plate; means mounted on the second sash engaging the pawl and urging the same into locking position; a tongue extended outwardly yfrom the plate adjacent to the inner side portion of the first sash, in longitudinal alignment with the notches, and engageable with the pawl in the closed position of the sashes for moving the pawl into its retracted position; and a latch borne by the second sash and movable between a position releasably engaging the pawl in its retracted position `for holding the pawl in such 'a position, and a position disengaged from the pawl.

14. The mechanism of claim 1 wherein the first ratchet member is 1an elongated plate extended longitudinally of the path of movement of the sash, said plate having a longitudinallyfextended row of longitudinally spaced sawtooth, locking notches therein; wherein the second ratchet member includes a pawl mounted on the sash for movement between a locking position engaging the plate and in longitudinal alignment with the row of notches and a retracted position out of engagement with the plate; including means borne by the sash engaging the pawl and yieldably urging it toward plate engagement whereby upon registration of the pawl with one of the notches, the pawl enters the notch to limit further opening movement of the sash; and wherein the control means includes a camming arm borne by the support and movable between a retracted position when the sash is out of closed position and a camming position in the path of the pawl and engageable therewith in the closed position of the sash, and means borne by the sash engageable with the arm in the closed position of the sash for urging the arm into said camming position thereby to press the pawl into its retracted position.

l5. The mechanism of claim 14 wherein the plate has an elongated slot adjacent to said arm; wherein a housing is secured to the sash and provides a surface in opposed adjacent spaced relation to the plate, said housing including a bore disposed transversely of said path of movement and registrable with said slot in the closed position `of the sash; wherein the pawl is slidably received in the bore; wherein the arm is pivotally mounted on the plate and is moved through the slot into the bore by said arm urging means for moving the pawl into the bore inwardly of said surface in the closed position of the sash.

16. The mechanism of claim 15 wherein said arm urging means is a iinger secilred `to the housing and disposed transversely of the arm in spaced relation to the pivot axis therefor.

17. In a support, a substantially rectangular frame circumscribing an opening, and a sash lmounted in the frame for slidable movement in opposite directions along a predetermined path between open position and a closed position in said opening; a mechanism optionally operable in an open position of the sash for limiting opening movement thereof until the sash is iirst moved into closed position comprising an elongated ratchet plate; means mounting the ratchet plate on the frame in longitudinally extended, adjacent relation to the path of movement of the sash, the plate having a row of notches therein facing the sash and longitudinally spaced and aligned along the plate; a housing supported on the sash for movement therewith; a pawl slidably mounted in the housing in a plane coincident with said notches of the-plate for movement transversely of said path between a locking position extended from the housing and adapted for extension into one of the notches upon registration therewith, and a retracted position retracted into the housing; resilient means in the housing yieldably urging the pawl into said locking position; and means borne by the ratchet plate engageable with the pawl for urging the pawl into a retracted position incident to movement of the sash from an open position into closed position.

18. The mechanism of claim 17 wherein the pawl has a recess therein; and including .a latch borne by the housing and slidably movable between a latching position extended into the recess of the pawl when the pawl is in a retracted position, and an unlatched position Withdrawn from the recess.

19. The mechanism of claim 18 wherein the latch has a predetermined path of travel in moving between said latching and unlatched positions, the pawl being in the path of travel of the latch when the pawl is in said locking position to preclude entry of the latch into the recess unless the sash is moved into closed position.

20. In a lock-ing mechanism including a body having spaced iirst and second bores yinterconnected by a passageway; a locking member mounted in said iirst bore for movement between predetermined locked and unlocked positions and having a notch facing said passageway in said unlocked position; a latch having latehing and blocking projections extended in angular relation to each other, the latch being slidably mounted lin the passageway for movement between latching position with the latching projection extended into the notch of the locking member when the latter is in its unlocked position, and an unlatched position with said latching projection retracted into the passageway, said blocking project-ion having a predetermined path of 4travel incident to movement of the latch in the passageway; and latch control means mounted in the second bore for movement between a blocking position in the path of ltravel of said blocking projection to limit movement of said latch in the passageway and a retracted position 'out of said path.

References Cited in the tile of this patent UNITED STATES PATENTS 594,620 Riddelle Sept. 5, 1893 570,503 Robertson Nov. 2, 1896 1,536,357 Simonovitz May 5, 1925 1,769,951 Hill July 8, 193) 2,047,937 Bohn et al July 21, 1936 2,072,300' Goetzmann Mar. 2, 1937 2,153,819 Van Voorhees Apr. 1l, 1939 2,192,519 King Mar. 5, 1940 2,699,204 Davis Ian. 1l, 1955 2,807,045 Chenoweth Sept. 24, 1957 

1. IN A SLIDING CLOSURE INCLUDING A SUPPORT PROVIDING AN OPENING AND A SASH SLIDABLY FITTED IN THE SUPPORT FOR MOVEMENT IN OPPOSITE DIRECTIONS ALONG A PREDETERMINED PATH BETWEEN OPEN AND CLOSED POSITIONS IN THE OPENING, A MECHANISM FOR LIMITING OPENING OF THE SASH COMPRISING A FIRST RATCHET MEMBER BORNE BY THE SUPPORT; A SECOND RATCHET MEMBER MOUNTED ON THE SASH AND MOVABLE BETWEEN A LOCKING POSITION ENGAGING THE FIRST RATCHET MEMBER TO PRECLUDE OPENING OF THE SASH BEYOND A PREDETERMINED OPEN POSITION, AND A POSITION RETRACTED THEREFROM PERMITTING UNRESTRICTED SLIDING OF THE SASH INTO FULLY OPEN POSITION, SAID SECOND RATCHET MEMBER BEING YIELDABLY URGED INTO LOCKING POSITION; CONTROL MEANS ENGAGEABLE WITH SAID SECOND RATCHET MEMBER AND OPERABLY ASSOCIATED WITH THE FIRST RATCHET MEMBER TO MOVE THE SECOND RATCHET MEMBER INTO RETRACTED POSITION ONLY WHEN THE SASH IS IN FULLY CLOSED POSITION; AND A LATCH RELEASABLY ENGAGEABLE WITH THE SECOND RATCHET MEMBER TO HOLD IT IN RETRACTED POSITION. 